Lighting, Light Fixtures, Ceiling and Exhaust Fans - Adding 3 way switch

Hi,
By code I need to add a switch at the bottom of my to be finished basement stairs to the light that exists there now and is controlled by an upstairs switch. The switch at the top is a 2way to the basement light and is inaccessible. Do I need to rewire the whole thing, ie. open the upstairs wall to add 3/1 romex into the upstairs box to connect to the downstairs switch and light? Or is there some way to use the existing switch and wire? The wire is 60 year old BX type with 2 wires in it.
Thanks.
Steve

You will have to run 12-3 (0r 14-3 if 15amp) from the original switch box to the new switch. Of course, the original switch will have to be replaced with a 3way switch.

I did this same thing recently to add a second switch for our living room (previous owner added second entry to room but did not add switch at entry). In my case, I had access from the attic and from the crawl space, so it was not a problem to fish wires into the wall. I choose to use the attic.


If your basement is unfinished, is there a chance you can access the wall the old switch is on from below and fish Romex up into the wall?


Just FYI, here's how I did mine: (and I may tell you wrong on which wire I used where as I don't recall exactly. Other posters can clarify which wires are *correct* to use as travelers vs. common.)
1. Turn off breaker
2. Remove existing switch (only one Romex into box: white taking power to switch, black returning power to light).
3. Remove box (in my case, I pried empty box loose from studs and let it drop to bottom of the hollow wall.
4. Drop one end of 12-3 from attic into wall and out opening for the box (existing extra hole in top plate of wall saved drilling new hole :) )
5. Feed 12-3 and existing 12-2 into box and mount box.
6. Connect white from 12-2 to common screw of the new 3way, wirenut the two blacks together, and connect white and red from 12-3 to two traveler screws of new 3way.
7. Run 12-3 to new switch location and into box.
8. Black to common, white and red to travelers.


I did step #3 because I couldn't think of an easy way to fish the wire into the box with the box iin the wall. Others here have suggested methods of doing that which would have worked without removing and replacing the box.

If power goes to your switch, then to your light, removing/replacing the box would be harder since there would be at least two sets of wires in the box.

chickware provided the standard way of doing it. But for about $30 at your home center, you can buy a battery-operated remote switch that just sticks on the wall at the bottom of the stairs. The switch at the bottom of the stairs is a transmitter and the switch at the top of the stairs (the one connected to the wires) is a receiver.

chickware provided the standard way of doing it. But for about $30 at your home center, you can buy a battery-operated remote switch that just sticks on the wall at the bottom of the stairs. The switch at the bottom of the stairs is a transmitter and the switch at the top of the stairs (the one connected to the wires) is a receiver.


Now you tell me!!! LOL

I had never heard of these. In the case where the old switch is inaccessable/difficult to access, that sounds like a wonderful solution. I'd have still done it the other way though since there was no major problem running the wire.


I suppose with these units that there is only a battery for the transmitter, correct? Could additional transmitters be added to give a third, fourth, etc. switch?

Thanks for the help. I wonder what my electrical inspector would say about a remote. He is pretty old school.
Steve